Question

For a common emitters transistor amplifier, the audio signal voltage across the collector resistance of $2k\Omega$ is 2 V. suppose the current amplification factor of the transistor is 100, the base current if base resistance is 1 $k\Omega$ is

• A. $10\mu A$
• B. $20\mu A$
• C. $5\mu A$
• D. $2\mu A$

Answer 1

Answer: (A)

$10\mu A$

Answer 2

: here,$R_{C} = 2k\Omega = 2000\Omega,R_{B} = 1k\Omega = 1000\Omega$

$\beta = 100,V_{o} = 2V$

$\therefore\beta = \frac{I_{C}}{I_{B}} = \frac{V_{o}/R_{C}}{I_{B}}$

$\therefore$Base current, $I_{B} = \Omega\frac{V_{o}}{\beta R_{C}}$

$= \frac{2}{100 \times 2000} = 10^{- 5}A = 10\mu A$